Abstract:Silica and other inorganic carriers are one of the major groups used to transport drugs and bioactive molecules into cells. The others are viral carriers, organic cationic compounds and recombinant proteins. The use of mesoporous silica can provide two advantages: a plasmid can be adsorbed on the external surface of the silica and a drug or fluorochrome can be adsorbed or covalently grafted on its mesoporous internal structure. Bare and PEGylated silica nanospheres (80 nm) have been synthesized, characterized and successfully coupled to pGL4.13 vector (plasmid). Standard protein adsorption experiments were carried out in order to analyze the potential avoidance of the reticuloendothelial system achieved with those nanoparticles. In vitro biocompatibility of bare and PEGylated silica nanoparticles was assessed in cultures of human tumor cell lines (Hela and Saos-2) and mesenchymal cells derived from human bone marrow of healthy donors (hMSC). After exposure for 24 h to nanoparticles, actin cytoskeleton was well organized in the three cell types examined. When the incubation period was extended to 72 h, PEGylated silica impaired metabolic activity to cells to a higher extent than bare nanoparticles. Hela and Saos-2 tumor cells exhibited a significant higher sensitivity to both types of nanoparticles than hMSC did.